Furnace wall and support construction



Sept. 12, 1961 w. H. ARMACOST 2,999,483

FURNACE WALL AND SUPPORT CONSTRUCTION Filed Nov. 8, 1957 3 Sheets-Sheet 1 FIG. I

WILBUR H. ARMACOST INVENTOR ATTORNEY Sept. 12, 1961 w ARMACOST 2,999,483

FURNACE WALL AND SUPPORT CONSTRUCTION Filed Nov. 8, 1957 3 Sheets-Sheet 2 FIG. 3

WILBUR H. ARMACOST INVENTOR ATTORNEY Sept. 12, 1961 w. H. ARMACOST FURNACE WALL AND SUPPORT CONSTRUCTION 3 Sheets-Sheet 3 Filed NOV. 8, 1957 WILBUR H. ARMACOST INVENTOR 2 A4 fflw ATTORNEY 2,999,483 FURNACE WALL AND SUPPORT CONSTRUCTION Wilbur lLArmacost, Scarsdale, N.Y., assignor to Combustion Engineering, Inc, New York, N.Y., a corporation of Delaware Filed Nov. 8, 1957, 82:. No. 695,324 8 Helms. (Cl. 122--510) This invention relates to the construction and Support of the furnace wall, or Walls, of a water tube boiler and has particular relation to boilers of the once-through type.

In the boilers of the type such as are currently being designed and erected for operation at supercritical pressures, the water is forced through a number of continuous circuits from the entrance of the water into the boiler to the discharge of steam from the boiler. As a result of employing these continuous circuits, which include long lengths of continuous tubing, it is necessary to line the inner surface of the furnace walls with tubes which are bent and formed in sinuous or serpentine fashion. This presents a challenging problem with respect to the support of the furnace particularly when it is considered that the temperature along the length of each of the tubes may be continuously changing and increasing in the direction of fluid flow, and also when it is considered that adjacent tubes may be at difierent temperatures, all of which result in difierential expansion of the tubes.

In accordance with the present invention the furnace is provided with a number of vertically extending tubes at each of its corners and which line the inner surface of the furnace at the corners. The upper ends of these tubes are connected to suitable headers which are preferably supplied with the fluid medium of the boiler from a common source in order that these corner tubes will be generally at the same temperature. These corner tubes are hung from a suitable framework at the upper end of the boiler through the means of hanger rods that extend from this framework with these corner tubes thus being free to expand downward. Between each set of corner tubes on each wall there is provided a group of adjacent parallel sinuously bent tubes which substantially completely line the inner surface of each of the walls between these respective corner tubes. These sinuously bent tube groups are supported from the corner tubes by means of a generally horizontal support element which extends across each of the walls adjacent the backs of the tubes and is secured at each of its ends to these corner tubes so that it is carried by the corner tubes. This support member is also secured to the sinuously bent group of tubes in a manner to support this group of tubes and also in a manher to provide for whatever differential expansion the respective tubes require.

t is an object of this invention to provide an improved wall construction for a boiler of the once-through type.

Other and further objects of the invention will become apparent to those skilled in the art as the description proceeds.

With the aforementioned objects in View, the invention comprises an arrangement, construction and combination of the elements of the inventive organization in such a manner as to attain the results desired as hereinafter more particularly set forth in the following detailed description of an illustrative embodiment, said embodiment being shown by the accompanying drawing wherein:

FIG. 1 is a diagrammatic illustration in the nature of a vertical sectional view of a once-through steam generator embodying the present invention;

FIG. 2 is a transverse sectional view of the furnace of the steam generator of FIG. 1 and is taken generally along line 2-2 of FIG. 1;

FIG. 3 is a front view of one of the walls of the furnace Patented Sept. 12, 1961 "ice 2 showing the tube arrangement lining the inner surface of the walls, per se, and is taken generally from line 3-3 of FIG. 2;

FIG. 4 is a detailed view of the interconnection of the horizontally extending support with the sinuously bent tubes intermediate the vertically extending corner tubes and is taken generally from line 4-4 of FIG. 3;

FIG. 5 is a front View of this interconnection of the sup port with the sinuously bent tubes as enclosed within the circle indicated in FIG. 3;

FIG. 6 is a detailed sectional view of the interconnection of the horizontal support with the vertically extending corner tubes and is taken along line 6-6 of FIG. 3;

FIG. 7 is a detailed perspective View of one of the inlet headers of the corner tubes showing the configuration of the header and showing its connection with the hanger rods;

FIG. 8 is a view similar to that of FIG. 3 but showing a modified form of the invention;

FIG. 9 is a detailed view of the spring connection of the horizontal support member with one of the tubes of the sinuously bent group, and is taken from line 99 of PEG. 8.

Referring now to the drawing, wherein like reference characters are used throughout to designate like elements, the invention illustratively depicted therein includes a once-through boiler that has a furnace 10 which, as disclosed, is tangentially fired by means of burners 12 that are located in each of the corners of the furnace although it is to be understood that other well know methods of firing may be employed if desired. The furnace 10, which, as disclosed, is upright, has an outlet 14 at its upper end through which the combustion gases generated in the furnace pass and which leads to the horizontal gas pass 16 which is, in turn, connected with the downwardly extending gas pass 18.

The fluid medium of the boiler, which is generally water, is supplied to header 2%) by means of a suitable pump and from this header is directed through the tube bundle 22 located in gas pass 18 and enters header 2 This header is connected with distribution header 25 through conduit 23 so that the fluid is conveyed to header 26 from which it is distributed to the four angularly formed headers 30 at the upper end of the furnace. Extending downwardly from each of these headers is a vertically dispose group of tubes identified as 32, which line the inn r surface of the furnace wall at each of the corners, as best shown in FlG. 2, with there being seven tubes in each group in the illustrative embodiment although it is to be understood that the number of tubes in these groups may vary as conditions demand.

Between each group of vertically extending corner tubes 32 on each wall is a group of adjacent parallel tubes that are sinuously bent so as to form What may be termed a panel that completely fills the space between the tube groups 32. on each wall and lines the inner surface of this space. In the illustrative organization of FIGS. 1 through 7 and referring particularly to FIG. 3, the sinuously bent group of tubes, which group is identified as 34, extend back and forth across the space between the groups of corner tubes 32 with the tubes in the sinuously bent group being coplanar and internested as shown. FIG. 3 illustrates the construction of one of the walls with each of the four walls of the furnace being constructed in a like manner.

Fluid admitted to headers 30 from distribution header 26 passes downwardly through the tube groups 32 which are connected at their lower ends to headers 36 that are similar to headers 30. The headers 36 that are adjacent side wall 38 are connected with header 40 of the sinuously bent group of tubes on this side wall while the headers 36 adjacent side wall 42 "are connected with headers 40 of the sinuously bent group of tubes on this side wall. The fluid thus flows upwardly through the sinuously bent tubes on each of these side walls to the outlet header 44 at the upper end of the furnace from which the fluid passes to header 46 through conduits 48. This header is in turn connected with the tube bundle 50 in gas pass 16 and from this tube bundle the fluid passes to the inlet header 52 of the sinuously bent group of tubes 34 in rear wall 54 where the fluid is heated to its generally desired temperature and supplied to the turbine or other point of use.

In the illustrative organization the sinuously bent group of tubes 34 that are disposed on the front wall of the furnace are for reheating purposes with the fluid (generally steam) being delivered from the turbine or other point of use, after a portion of its energy has been utilized, to the reheater where it is reheated to a desired pressure and temperature. However, it is to be understood that the various relationships and purposes of the heat exchange surface may be varied as desired, and that the organization herein shown and described is merely illustrative of one of a large variety of arrangements that may be utilized.

The steam generator of this invention, as is usual in present day practice, is hung from its upper end so that it can expand downwardly as a result of thermal expansion. In order to thus support the steam generator there is provided a structural framework which includes the upright support columns 60 to which are connected at their upper ends horizontal structural members 62. The vertically disposed groups of tubes 32 at the corners of the furnace are hung from the structural members 62 by means of the support rods 64 that extend downwardly from the structural members and are connected to the angularly formed headers 30 (FIG. 7) with these headers being formed with upstanding ears 66 which are connected with the lower end of the rod 64 by a suitable pin or in any other desired manner. With the groups of tubes 32 thus hung from above they may act as corner columns for supporting the entire furnace and accordingly the sinuously bent group of tubes 34 that line the inner surface of each of the furnace Walls between these corner tubes are supported from the corner tubes. For this purpose there is provided a plurality of horizontal support members or beams 68 at vertically spaced locations throughout the length of each of the Walls. These horizontally disposed support members are vertically located as shown in FIG. 3 and in overlying relation with each set of return bends 70 of the sinuously bent group of tubes 34. Each of the members 68 is secured directly to the vertically extending group of tubes 32 as by welding 72 (FIG. 6) and is secured to its respective overlying return bends 70 by means of the angularly offset member 74 one of which is secured to the return bend of each tube with this olfset member being slidingly received behind the adjacent flange or lip 76 of the support member 68. With this construction, vertical support for the sinuously bent group of tubes is provided as well as a means for keeping the tubes in alignment while at the same time permitting horizontal movement of the horizontal tube runs of this group relative to the support member and relative to each other. It will be necessary to provide for such relative movement of the horizontal tube runs of the group 34- for the reason that each of the tubes may be at a somewhat different temperature and the temperature of the tubes throughout their length will be varied considerably. The tubes of the group 34 are of course spaced suificiently to accommodate this differential movement and the vertical extent of the U-bends is sufficient to flex the amount required to accommodate relative movement between successive horizontal tube runs of each tube.

Since the first and last horizontal tube run of the group of tubes 34 would be supported by one of the support beams 68 only at one end of the tube run it may be desirable to secure the other end of this tube run to the vertically extending tube group 32 to which it is adjacent and for this purpose the tube group 34 may be welded to the adjacent tube of the vertically extending group 32 at 78, as shown in FIG. 3.

With this organization the sinuously bent tube groups 34 are supported by the vertically extended tube groups 32.

Since the tube groups 32 are connected with the common header 26 so that they receive their fluid from a common source they will be at substantially the same temperature so that difierential expansion between the several groups will be held to a minimum with this being desirable although not essential in order to maintain the bending of the support members 68 at a minimum and the stress of the connection of these members with the tubes of group 32 at a The embodiment of FIG. 8 discloses a different disposition of the sinuously bent group of tubes that line the furnace wall between the groups of corner tubes 32. In this embodiment the group of sinuously bent tubes 78 are identified as 80, 82, 84 and 86, with these tubes, which are adjacent and coplanar, extending up and down the length of the furnace wall rather than across the furnace Wall. With this construction the group of tubes 78 may be supported from the corner groups 32 by means of a single horizontal support member or beam 79 which is welded directly to the tubes of groups 32 as in the previously described embodiment. This support member is positioned at or below the hairpin on innermost return bend of the tube group 78 at the upper end of the wall. The support member 79 is secured directly to the sinuous or serpentine group 78 in the same manner as it is secured to the tube of groups 32, i.e., welded directly to the tubes, with the exception of the vertical tube runs that are adjacent the innermost return bend at the lower end of the wall.

For explanation purposes it will be considered that the first vertical tube run of group 78 forms panel 88, the second vertical run forms panel 90, the third tube run forms panel 92 and the fourth forms panel 94. Tubes 80, 82, 84 and 86 of panel 88 are secured directly by welding to support member 79. Since the tube runs in panels .88 and 90 may expand differently because the temperature throughout the length of each tube may increase in the direction of fluid flow through the tube, tubes 86 and 84 of panel 90 should not be welded to support member 79 since the horizontal extent of the U-bends 96 and 98, respectively, will not be sufficient to bend the amount required to accommodate the resulting differential expansion of these tube mus. Therefore tubes 86 and 84 of panel 90 are connected to support member 79 by means of a spring connection while tube 82 and of this panel may be welded directly to the support member 79 since the horizontal extend of their U-bends will be sufficient to accommodate the differential expansion between the vertical run in panel and that in panel 88. In panel 92, tubes 84 and 86 are connected to support member 79 through a spring connection while tubes 80 and 82 are directly welded to the support member while in panel 94 tubes 80, 82, 8'4 and 86 are all welded directly to the support member 79. Through this arrangement diiferential movement of the interconnected vertical tube runs in each of the panels may be had.

The spring connection between support member 79 and tubes 84, 86 is shown in detail in FIG. 9 and comprises support bracket .100 that is secured to and extends downwardly from support member 79. To the lower end of this bracket is secured spring 102 which is connected at its lower end to a similar bracket 103 which is, in turn, secured to lug 107 welded to and extending laterally from the tube.

With this embodiment of FIGS. 8 and 9, as in the embodiment of FIGS. 1 through 7, the sinuously bent tube groups which line the portion of the inner surface of the furnace wall lying between the corner tube groups 32 is supported from the corner tube groups. It will, of course, be understood that FIG. 8 shows only a single wall and that in this embodiment each of the furnace walls will be constructed in a manner similar to that shown in this figure.

While I have illustrated and described a preferred embodiment of my invention it is to be understood that such is merely illustrative and not restrictive and that variations and modifications may be made therein Without departing from the spirit and scope of the invention. I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes as fall within the purview of my invention.

What is claimed is:

1. In combination, a once-through boiler including an upright furnace of polygonal transverse section, a plurality of tubes lining the inner surface of each corner of the furnace and extending vertically throughout the length of the furnace, said tubes forming part of the circuit of the boiler and being supported from above, a number of tubes bent in serpentine fashion and disposed in the plane of each of the furnace walls substantially filling the space between said corner tubes and forming the inner surface of the wall between said corner tubes with these serpentine tubes also forming a part of the circuit of the boiler, horizontal structural support members extending across each of the walls at vertically spaced locations throughout the length of the wall and in juxtaposition to the portions of the tubes remote from the furnace interior, said support members being carried by the vertically extending corner tubes at each end of each wall and with said serpentine tubes intermediate said corner tubes being carried by said support members while permitting said serpentine tubes to expand and contract as required by variations in temperature of the tubes.

2. A boiler of the once-through type having an upright furnace of polygonal transverse section characterized by a group of tubes disposed in each corner of the furnace and extending vertically throughout the length of the furnace, with said tubes lining the inner surface of the furnace at the corners and being supported from above so that they effectively provide a column at each corner for supporting the remainder of the wall, a group of tubes disposed intermediate the corner tubes of each wall with these intermediately disposed tubes being sinuously bent in a common plane and lining the inner surface of the particular wall and with some of said groups being in series flow relation with the corner tubes, means supporting the sinuously bent tubes lining each wall from the vertically extending tubes in the particular wall at the corner of the furnace, said means comprising an elongated support member extending laterally across the wall on the side remote from the furnace interior and connected at its ends to said corner tubes so that it is supported thereby, and means interconnecting the sinuously bent tubes intermediate these corner tubes with said member so that they are supported thereby and with said last-named means providing for relative movement between the tubes and support where required to permit successive tube runs to expand and contract relative to each other.

3. The organization of claim 2 wherein the group of sinuously bent tubes of each wall extend back and forth in a generally horizontal direction between the spaced vertically extending tubes in each wall at the corner of the furnace, and wherein there are a plurality of support members at the bend of each tube being connected with an elongated support member with a connection that provides vertical support but permits lateral movement of the tube relative to the elongated support restricted to a direction parallel with the wall.

4. The organization of claim 2 wherein the tubes of each of the groups of sinuously bent tubes of each wall are in adjacent side by side relation and extend up and down in a vertical direction between the spaced vertically extending tubes in each wall at the corners of the furnace with the tubes forming internested U-bends at the upper and lower ends of the wall, with each vertical run of each group of tubes effectively forming a panel and with these panels being in side by side relation, said support member being connected to the vertical runs of these tubes adjacent their upper ends with a number of the runs of one of the panels of each pair that are interconnected at the lower end and which runs are nearest the other panel of the pair being connected with the support mem bers by a spring connection which allows vertical movement of these tubes with respect to the support member.

5. A boiler of the once-through type having an upright furnace of polygonal transverse section characterized by a group of tubes disposed in each corner of the furnace and extending vertically throughout the length of the furnace, with said tubes lining the inner surface of the furnace at the corners and being supported from above so that they effectively provide a column at each corner for supporting the remainder of the wall, a group of tubes disposed intermediate the corner tubes of each wall with these intermediately disposed tubes being sinuously bent in a common plane and lining the inner surface of the particular Wall and with these sinuously bent. tubes on some of the walls being in series flow relation with the vertical tubes in at least some of the corners, means sup porting the sinuously bent tubes lining each wall from the vertically extending tubes in a particular wall at the corner of the furnace, said means comprising an elongated support member extending laterally across the wall on the side remote from the furnace interior and connected at its ends to said corner tubes so that it is supported thereby, and means interconnecting the sinuously bent tubes intermediate these corner tubes with said member so that they are supported thereby.

6. A once-through boiler including an upright furnace of polygonal transverse section, a group of side by side tubes disposed in each corner of the furnace and extending vertically throughout the length of the furnace with said tubes lining the inner surface of the furnace at the corners and forming a part of the circuit of the boiler, and with the groups of tubes of the several corners being connected to a common source so the fluid flowing therethrough is at substantially the same temperature, means supporting said tubes from above so that the tubes effectively provide a column at each corner for supporting the remainder of the wall, a group of adjacent, parallel tubes intermediate these corner tubes and also forming part of the circuit of the boiler, with these intermediately disposed tubes being sinuously bent in a common plane and lining the inner surface of the particular wall, and with these sinuously bent tubes on some of the walls being in series flow relation with the vertical tubes in at least some of the corners, means supporting the sinuous bent tubes lining each wall from the vertically extending tubes in the particular wall at the corner of the furnace, said means comprising an elongated support member extending laterally across the wall on the side remote from the furnace interior and connected at its ends to said corner tubes so that it is supported thereby, and means interconnecting the sinuously bent tubes intermediate these corner tubes with said member so that they are supported thereby.

7. An upright fluid cooled furnace wall comprising in combination a plurality of side by side vertically extending tubes at the lateral extremities of the wall with these tubes lining the inner surface of the wall at these extremities, means supporting these tubes from above, a plurality of juxtaposed parallel, serpentine formed tubes disposed between the tubes at the lateral extremities of the wall with the serpentine tubes lining the inner surface of said wall therebetween, means for supporting said serpentine tubes comprising a support member extending across the back sides of the tubes remote from the inner surface of the wall, said member supported by the vertical tubes at the extremities of the wall and effectively connected to the serpentine tubes in a manner to support the same.

.7 g 8. The organization of claim 7 wherein the connection References Cited in the file of this patent of the support member and at least some of the serpentine UNITED STATES PATENTS tubes is loose and permits relative movement between the 2 281 580 Hobbs May 4 tubes and the Supp member difiaren' -2:681:641 Andrew et ZIIIIIZTJune 22: 1954 tial expansion and contraction of said tubes as required. 2,697,420 Lloyd 1954 

